The liver plays a central role in energy and nutrient metabolism. Liver disease results in complex pathophysiologic disturbances affecting nutrient digestion, absorption, distribution, storage, and utilization (1). Nutritional deficiencies are frequent in children and adults with chronic liver disease, especially patients with cholestasis. Nutritional deficiencies in children are commonly observed in pediatric patients such as biliary atresia (BA), Alagille syndrome, progressive familial intrahepatic cholestasis, and cystic fibrosis (2,3). Cholestasis is defined as the impairment of bile flow, either from hepatocellular dysfunction or from biliary obstruction (4,5). In patients with cholestasis, an inadequate quantity of bile salts are delivered to the intestinal lumen and, consequently, result in fat and fat-soluble vitamin (FSV) malabsorption and deficiency (6). Deficiencies in FSVs induce multiple clinical complications. Night blindness is a frequent consequence of vitamin A deficiency. Vitamin D deficiency results in defective bone mineralization, causing rickets in children. Vitamin E deficiency causes neurologic problems because of poor nerve conduction. Vitamin K is required for the posttranslational carboxylation of glutamic acid residues on coagulation factors II, VII, IX, and X, in addition to proteins C and S, within the liver. Vitamin K deficiency induces abnormal coagulation function as manifested by easy bruising or a bleeding diathesis (1,4). FSV deficiencies in children with cholestatic disease have been reported, but the prevalence and severity are not clearly documented (1,3,7).
It is generally acknowledged that patients with cholestasis should be supplemented with FSV; however, the efficacy of FSV supplements, including parenteral route and enteral route, under present treatment is not clear. There are problems that existed under present practice of FSV supplementation in patients with cholestasis. Although there are general guidelines of FSV supplementation, the importance of such supplementation was often overlooked by patients/parents, or even by physicians because it was considered as a “supplement,” instead of a “medication” that is for the treatment of the diseases. The details of dosage, intervals, and formulation of FSV administration used in patients with cholestatasis varied widely among different physicians and different institutions. There also existed a large discrepancy between physicians’ decisions on what subpopulation of patients in what clinical severity need to be treated. For fear of overdose or toxicity, or for convenience, many patients were undertreated when clinical symptoms and signs of deficiency had not developed.
Recently, a novel water-soluble oral formulation of FSV mixture was developed. It safely and effectively increases the plasma levels of these important components in patients with cystic fibrosis (8). The formulation is potentially suitable for FSV supplementation in patients with chronic cholestasis. In the present study, we aimed to evaluate the present status of FSV deficiencies under routine practice in pediatric gastroenterology clinics, and to test the effect of this oral, absorbable, fat-soluble vitamin formulation (OAFSV) supplementation in pediatric patients with cholestasis.
We recruited a total of 23 pediatric patients ages 2 months to 18 years. All of the patients had a clinical diagnosis of chronic cholestasis, including BA (10), progressive familial intrahepatic cholestasis (9), Alagille syndrome (2), and other conditions (2). These patients had received regular follow-up for >3 months at pediatric gastroenterology clinics in a tertiary referral center and had received conventional FSV supplementation (Table 1). The conventional FSV supplements were given either orally once a day, using a commercially available oral infant vitamin supplement, or as an intramuscular (IM) injection of Multiva and phytonadione every 1 to 4 weeks in our hospital. The intervals of patients’ visits varied, according to the doctor's suggestions based on their clinical condition. All of the patients had been followed up and kept on their routine of FSV supplements for >3 months. Among the 23 patients, there were 15 patients receiving an IM injection of Multiva and phytonadione, 2 patients receiving commercially available oral infant vitamins, and 1 patient receiving both IM injection of Multiva and phytonadione and commercially available oral infant vitamins. Five patients were receiving no FSV supplements because of allergy or by doctor's decision. The commercially available oral infant vitamins were purchased from an over-the-counter pharmacy by parents because there were no oral multivitamin supplement formulations available in the pharmacy of our hospital. By present policy, Taiwanese national health insurance does not cover oral vitamin formulations for patients with cholestasis.
OAFSV Supplementation and Follow-up
Twelve patients chose to shift from conventional therapy to an OAFSV formulation (AquADEKs; Yasoo Health Inc, Johnson City, TN) for 3 months, according to the will of the patient and/or the family, either to avoid frequent painful injections or in anticipation of a better efficacy of FSV supplementation (Table 1). Patients younger than 1 year were administered a 1-mL AquADEK supplement daily. Patients older than 1 year were administered a 2 mL daily dose. All other medical treatments and medications were unaltered. Follow-up evaluations were conducted at 0, 1, and 3 months at pediatric gastroenterology clinics. Patient plasma levels of vitamins A, D, and E and the international normalized ratio (INR) for prothrombin time (PT), as a surrogate marker for vitamin K, were measured at 0 and 3 months after OAFSV supplementation. Any adverse reactions that were reported by the child and/or parent were documented. The study was approved by the institutional review board.
Plasma retinol and α-tocopherol were simultaneously determined by reversed-phase liquid chromatography with a programmable and variable UV wavelength detector to evaluate the status of vitamin A and vitamin E (9). The level of 25-hydroxyvitamin D was tested using a 25-hydroxyvitamin D 125I RIA Kit (DiaSorin, Stillwater, MN) (10). The deficiency level definitions for vitamins A, D, E, and K were based on previous reports. Vitamin A deficiency was defined as a plasma retinol level <1 μmol/L, and a toxic level was defined as >3 μmol/L (11,12). Vitamin D deficiency was defined as a 25-hydroxyvitamin D level <14 ng/mL and a toxic level as > 80 ng/mL (6,13). Vitamin E deficiency was defined as a plasma α-tocopherol level <23 μmol/L and a toxic level as >80 μmol/L (14). Vitamin K deficiency was defined as INR > 1.3 (15).
The proportion of FSV deficiencies between the different patient groups were calculated using Fisher exact test. The individual difference in biochemistry results between groups was calculated by the Wilcoxon rank sum test. The paired difference in the proportion of FSV deficiencies and the biochemistry results between the groups were calculated using McNemar test and the Wilcoxon sign rank test. All statistical analyses were performed using SPSS 18.0.
FSV Deficiencies in Pediatric Patients With Cholestasis Under Conventional Supplementation
The clinical characteristics of the 23 patients with chronic cholestasis are shown in Table 2. The FSV deficiencies were analyzed in these 23 patients before some were shifted to OAFSV. A high proportion of patients with vitamin A, D, and E deficiencies were found (73.9%, 81.8%, and 91.3%, respectively) under conventional supplementation, whereas the proportion of vitamin K deficiency was 20.0% (Table 3).
We then examined whether the biochemical parameters of cholestasis were associated with the development of specific FSV deficiencies. We found that total bilirubin (P = 0.02) and direct bilirubin (P = 0.03), but not other clinical parameters including aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, r-glutamyl transpeptidase (rGT), and serum bile acid, had a statistically positive association with vitamin D deficiency. Using receiver operating characteristic (ROC) curve analysis, we found that a total bilirubin level ≥3.0 mg/dL or direct bilirubin levels ≥2.8 mg/dL were greatly predictive of the occurrence of vitamin D deficiency (sensitivity 77.8% and 72.2%, specificity 100.0% and 100%; P < 0.01 and P < 0.02, respectively). In addition, serum rGT levels were also found to be positively associated with vitamin E deficiency (P = 0.02). Serum rGT levels >250.0 U/L predicted vitamin E deficiency (sensitivity 100.0%, specificity 95.2%; P < 0.01).
For quick clinical reference, we examined predictive value of total bilirubin level in predicting all FSV deficiencies. The sensitivity of total bilirubin levels ≥3.0 mg/dL in predicting vitamin A, D, E, and K deficiency was 64.7%, 77.8%, 66.7%, and 75.0%, respectively. The specificity of total bilirubin levels ≥3.0 mg/dL in predicting vitamin A, D, E, and K deficiency is 50%, 100%, 100%, and 31.3%, respectively. In patients with total bilirubin levels ≥3.0 mg/dL, the proportion of at least 1 FSV deficiency was 100%. The deficiency rates of vitamin A, D, E, and K were 78.6%, 100.0%, 100.0% and 21.4%, respectively (Table 4). On the contrary, patients with a direct bilirubin level <3.0 mg/dL tended to have lower rates of deficiencies, yet still had a high incidence (77.8%) chance of at least 1 FSV deficiency. The positive, negative predictive values, and diagnostic accuracy of total blirubin ≧3.0 mg/dL for at least 1 FSV deficiency were 100%, 22.2% and 69.6%, respectively.
Patients Supplemented With OAFSV
Of the 23 patients under analysis, 12 chose to shift to OAFSV with the patient's consent. The clinical parameters including age, weight, height, and biochemical data between the patients shifting to OAFSV and those who continued conventional therapy were not significantly different (supplementary table, http://links.lww.com/MPG/A114). During follow-up, 2 patients discontinued the OAFSV formulation within 1 month owing to an unacceptable taste. The 2 patients who dropped out from OAFSV group were shifted back to conventional treatment, and have received regular follow-up at our clinic. Ten patients completed the 3-month course and were included in subsequent analysis.
The rates of vitamin A, D, and E deficiency after receiving the OAFSV formulation for 3 months decreased from 80.0%, 100%, and 100% to 70.0%, 60.0%, and 60.0%, respectively, with borderline significance (P = 1.0, 0.09 and 0.09) (Table 3). Only 1 patient had vitamin K deficiency before receiving the OAFSV formulation, and no patient had vitamin K deficiency after receiving the OAFSV formulation for 3 months. The follow-up plasma levels of vitamin A, D, and E of these 10 patients are shown in Figure 1.
No apparent adverse events were noted during our study period in all of the patients including the patients receiving parenteral and enteral vitamin supplementation. No patients had vitamin levels rise to toxic levels.
Our results indicate that the prevalence of FSV deficiencies is strikingly high in pediatric patients with cholestasis under present medical care and regular follow-up. Symptoms of FSV deficiencies are subtle and may not be clinically apparent until severe cholestasis presents over months or years; however, without adequate supplementation, patients may experience multisystem organ dysfunction over a long period (16–19). The present study, showing the present status of FSVs in the “conventional group,” revealed the reality of everyday practice in our institution, and probably the similar situations in many other places. We aimed to point out the underestimated prevalence of subclinical FSV deficiencies, and possible alternative methods of FSV administration in the present study that may improve compliance in some patients.
The lower prevalence rate of vitamin K deficiency in the present study was probably because of the deficiency criteria and using abnormal INR as a surrogate marker to represent the complication associated with vitamin K deficiency. In contrast, vitamin A, D, and E levels were defined by plasma levels when the patients were still asymptomatic. This may greatly underestimate the actual incidence of vitamin K deficiency because PT is a late indicator of vitamin K deficiency and can be normal even when prothrombin concentrations fall to half-normal values (20). The prevalence of subclinical vitamin K deficiency in cholestatic liver disease in pediatric patients has been reported to be approximately 68% by measuring plasma protein induced in vitamin K absence II (PIVKA-II) (15). Thus, the prevalence of vitamin K deficiency may be underestimated in our study.
Our data indicate an association between the severity of cholestasis and FSV deficiencies. Among the commonly used clinical laboratory tests including total bilirubin, direct bilirubin, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, rGT, and serum bile acid, we found that higher bilirubin levels were positively associated with vitamin D deficiency. A total bilirubin level ≥3.0 mg/dL or direct bilirubin level ≥2.8 mg/dL was useful in predicting vitamin D deficiency. There were also trends of association between bilirubin levels and vitamin E and K deficiency. It is possible that when the patient's number increases, the association may be more significant. For a quick clinical reference, we found a total bilirubin level ≥3.0 mg/dL as a simple criteria of great risk of FSV deficiency, with a high positive predictive value. All of the patients with a total bilirubin level ≥3.0 mg/dL experienced FSV deficiency with at least 1 vitamin type (Table 4). Studies indicated that a direct bilirubin level >2.0 mg/dL is predictive of long-term outcome after the Kasai operation in patients with BA (21). The frequency of FSV deficiencies in specific types of patients with cholestasis , such as BA, deserves further investigations; however, many may consider patients with a total bilirubin level <3.0 mg/dL to be at a low risk for FSV deficiency and may omit or overlook the necessity of supplementation. It is noteworthy that in our study, this patient group still had a 77.8% of chance of FSV deficiency. Therefore, a high index of suspicion and a better index to determine the lowest levels of cholestasis for necessity of FSV supplementation will require further studies to clarify.
The mainstay of conventional FSV supplementation is the frequent practice of IM injection. Compliance is variable owing to the painful injections in children. In addition, to receive the injection, patients need to be brought to the hospital, and this is a time- and cost-consuming task. In our study, the patients deciding to receive the OAFSV formulation may have poorer compliance with conventional supplementation, as reflected by a higher baseline proportion having vitamin D deficiency. Of note is that 2 patients who dropped out from OAFSV group were shifted back to conventional treatment, and have received regular follow-up at our clinic. It is important that the best effort be made for patient education on the importance of continuation of FSV supplements and consequences of FSV deficiency, no matter what type of supplementation they receive. Although supplementation of FSV is recommended in the treatment of cholestatic liver diseases, it is not routinely or properly used in clinical settings before complications occur, partly because of the complexity in supplying all of the required vitamins and partly because FSV are considered nutritional supplements and not mandatory therapeutic agents. For better medical treatment of patients with cholestasis , an optimal guideline for FSV supplementation is important. A high index of suspicion and the adequate promotion of the importance of FSV supplementation will benefit many patients.
In our study, the patients who received the OAFSV formulation for 3 months demonstrated decreased rates of vitamin A, D, and E deficiency from 80.0%, 100.0%, and 100.0% to 70.0%, 60.0%, and 60.0%, respectively, resulting in borderline significant benefits from the OAFSV formulation. A longer period of OAFSV supplementation is needed to evaluate whether the FSV status improvement is more significant and sustained.
Our study suggested a possible alternative choice of FSV administration with a starting dose that is easy to follow. No serious adverse effects were observed in the patients. The vitamin levels did not reach toxic levels or fall to more deficient levels in the patients receiving OAFSV supplementation. Patients with more severe cholestasis may require a higher dose or an increased frequency of FSV supplementation. The monitoring of FSV plasma levels is necessary to further titrate and optimize the dosages that should be given. Regarding the cost of OAFSV or conventional treatment, when taking into consideration the cost of time and efforts for parents and children to visit the hospital frequently, the cost because of absence from work and school, and the future possibility that OAFSV be covered by insurance, it is possible the overall cost will be comparable to IM injections, or cut down by using OAFSV.
There are several limitations of the present study. The number of patients was small. We were unable to clearly compare the effect between conventional and OAFSV treatment because this is not a controlled study. The largely variable age, disease severity, and nutritional status of the patients made the comparisons more difficult. Further studies involving greater patient numbers and long-term follow-up are necessary to optimize the FSV dosing according to the severity of patient cholestasis. For each formulation used, more clear and practical guidelines, and efforts to aggressively advocate the importance of FSV supplementation among patient groups and medical professionals are required to improve patient outcome and to prevent long-term complications.
FSV deficiencies occur frequently in pediatric patients with cholestasis with present practice of conventional supplementation. OAFSV supplementation is safe and potentially effective in pediatric patients with cholestasis. Further studies to optimize the dose and efficacy for preventing complications are required. FSV deficiency should be considered in patients with chronic cholestasis at any level of severity.
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